[axman88]

A new Vtwin retro of the KX would be great!!! However, who would be the target market? All the old fellas in vintage clubs call RE fake anyway (their loss) and harley riders wont swap! No way it would sell in india! Just not financially viable but here's hoping

I think you are referring to the Harley "K" model flathead engine, released in 1952?   There were various models, but none were "KX"    https://www.harleykmodel.com/index.html

The most famous "KX" moto, that I'm aware of, is Kawasaki's family of dirt bikes, still in production.   https://www.kawasaki.com/en-us/motorcycle/kx

If anybody was going to produce a retro motorcycle inspired by the Harley K sidevalve, I'd predict it would be Shineray.  They  have apparently decided to step into the considerable gap left when HD elected to close their Bawal India plant, cutting off the flow of Indian assembled Sportsters to Europe and Asia.
https://www.youtube.com/watch?v=KA1QgIY2ZC0
https://www.youtube.com/watch?v=lZu4qkfMAUo

I wondered what Shineray was planning to do with the engine they were showing around earlier this year:
https://bikereview.com.au/carbon-copy-shineray-replicate-harley-davidson-evolution-1200/ 

Now we know.

It seems that SWM, Shineray's Italian affiliate, has accomplished what so many claimed HD could not do, get the old aircooled, pushrod Vee engine to meet current euro emissions standards.

I'd suggest that it are those standards, that are the reason no manufacturer would take on the challenge of designing a modern side valve engine of any substantial capacity.  Even lawnmowers are going to overhead cams.

[Warwick]

K and KX Royal Enfield. An iconic Royal Enfield

[axman88]

K and KX Royal Enfield. An iconic Royal Enfield

Ahhh!  Of course.  And that's the answer to the OPs big question, too.  RE WILL, definitely make an 800-1200 cc bike!

A 1000 cc in 1930:
    https://www.yesterdays.nl/product/royal-enfield-1930-model-k-1000-cc-2-cyl-sv/

And an 1140 cc in 1938:
    https://www.financialexpress.com/auto/gallery/royal-enfield-kx-in-pictures-1140cc-v-twin-gear-shifts-by-hand-and-classic-looks-from-pre-war-era/photos/1155576/

It was a trick question!

[AzCal Retred]

You can always DIY if RE is taking too long...

https://auto.hindustantimes.com/auto/two-wheelers/in-pics-custom-himalayan-822-from-india-bike-week-is-an-adventurous-beast-41670051989998.html

https://timesofindia.indiatimes.com/auto/bikes/worlds-only-822cc-royal-enfield-himalayan-to-unveil-at-india-bike-week-2022/articleshow/95818733.cms

https://www.livemint.com/auto-news/custom-royal-enfield-himalayan-822-showcased-at-ibw-2022-all-details-11670153643214.html